Method for producing laminated sheet matrix containing releasable ingredient

ABSTRACT

A sheetlike article comprising a single-layer homogenous matrix containing at least one active substance such as a crop protection agent, biocide, fertilizer, plant strengthener, cosmetic substance or fragrance, is produced by applying the at least one active substance to at least one of two layers of identical composition, placing the two layers atop one another so as to enclose the at least one active substance, irreversibly joining the layers with the at least one active substance therebetween under pressure to form a laminate and storing the laminate under defined conditions for a duration sufficient to effect migration of the at least one active substance into the base layer and connection of the layers at their interfaces.

BACKGROUND OF THE INVENTION

The invention relates to a process for producing a sheetlike formulationcomprising at least one single-layer active substance matrix for thecontrolled release of active substance to the vicinity of theapplication site, the active substances being selected from cropprotection agents, biocides, fertilizers, plant strengtheners, cosmeticactive principles and fragrances.

Formulations, whose preparation is described below, are known from manyareas of life for which the time- and quantity-controlled release of oneor more active substances is required. Depending on the area of use,these formulations are applied in the form of sheetlike structures suchas labels, strips, pouches, plasters or plaques to certain substrates orobjects from which they develop their action. Typical fields of use forsuch products that may be mentioned here include, for example, pestcontrol, for example, in vineyards or in forestry, or for cropprotection, perfumery and cosmetology.

For reasons of cost, such formulations are wherever possible formulatedso that the active substance is contained in a flat, single-layerpolymer film from which in the course of the use the active substance isreleased to the site or the vicinity of application. In general, theseformulations have a layered structure, comprising at least one matrixlayer containing active substance and at least one support layer incontact with the matrix layer. These layers can be present in a“sandwich-like” form or are joined to one another at the sides andformed in the manner of a pouch. Depending on the field of use, they areusually also in fixed or detachable combination with differentfunctional layers such as, for example, control membranes or protectivelayers.

Processes for producing formulations of the type specified are known. Acommon feature of such preparation processes known from practice is thatthe formulation is first of all produced in the form of a strip-shapedweb embracing the active substance matrix, then combined, if desired,with other layers, and separated into sections of a desired size bypunching or cutting.

Because of the diversity of active substances applicable by means ofthese devices, and because of the different physicochemical propertiesof these active substances, the preparation of the single-layer activesubstance matrix represents the central step in such processes. Amongthe prior art processes for the preparation of such formulations, thedissolving or dispersing of the active substances in matrix material,usually a polymer solution or polymer melt, with subsequent drying, isprobably the process of choice for the person skilled in the art.However, not all active substances can be processed in this way. Theprocessing of volatile active substances proves to be particularlyproblematic, since the evaporation of the active substance during thepreparation is almost impossible to control. And temperature-sensitive,so-called thermally labile active substances can be used only withrestrictions, if at all, for systems requiring heat treatment during themanufacturing process.

For this reason, a variety of solutions have been worked out over thecourse of time to allow the preparation of the releasing matrices,especially for volatile and/or thermally labile active substances. Forexample, the principle of a depot is used, in which problematic activesubstances are introduced into a multi-part product in the form of adiscrete reservoir of active substance without thermal stress—forexample, in a separate process step during preparation. Processes ofthis kind in which the preparation of matrix layers free from activesubstance and the introduction of the active substance into the producttake place as temporally and spatially separate operating steps areknown from the manufacture of numerous products but are verylabour-intensive.

In accordance with the prior art, active substance can be incorporatedinto a matrix using a variety of techniques. For instance, theintroduction of a flowable active substance medium under pressure, inaddition to the pressurized insertion of a solid active substance body,and injection, belongs to known processes of incorporating activesubstance into solid matrices. The processes mentioned have the commonfeature that active substance is applied initially to a support on whichit remains only temporarily, since it migrates into the matrix layersthat are in contact with it. Constituents which prevent unwanted flow orescape and whose function is to halt the active substance temporarilyare referred to in the technical literature using terms such as, forexample, adsorption layer, active substance dispenser, active substancesupport, fixing aid, support material, and interlayer. Liquid-absorbingsubstrates suitable for this purpose include nonwoven, foam, paper orwoven textile material.

In practice, however, known production processes are frequentlyassociated with disadvantages, a selection of which is specified below,and, as a result, prove to be correspondingly complex:

The absorption capacity for liquid media is generally limited to acertain level, which is frequently a limiting factor in loading thematrix with active substance.

In order to obtain controlled, continuous release of active substanceover prolonged periods of application and to rule out the possibility ofunwanted side-effects caused by excessive release rates, an additionalcontrol layer is often necessary.

The use of additional materials prolongs production and complicates ittechnically, since the individual layers and elements must first bemanufactured separately from one another and then combined with oneanother in one or more subsequent steps.

The use of additional elements may also impair the performance qualitiesof the product, especially the shear stability, since the incorporationof an active substance fixing means reduces the contact area betweenmatrix layers which are to be united. In order to ensure, despite this,the desired structural integrity of the formulation, there is often aneed for additional connecting areas, in the form, for example, of aperipheral adhesive edge, which result in an unwanted increase in thedimensions.

The embedding of additional support materials may, furthermore,adversely affect the flexibility and functionality of the product. Thisis particularly so if thicker layers are necessary as a result of a lowabsorptive capacity, e.g. the absorbency of the material. Thesedisadvantages are extremely undesirable especially in the case of activesubstance patches applied to surfaces of plants.

The morphology of the higher plants, especially the low radius ofcurvature and the lack of evenness and cleanliness of surfaces ofplants, indeed, imposes particularly stringent requirements on theflexibility and small dimensioning of such active substanceformulations. Added to this are the severe conditions borne by thesurfaces of plants as a result of natural weather conditions at the siteof application, which increases their susceptibility to a possible lossof cohesion.

SUMMARY OF THE INVENTION

Because of the disadvantages described above, multilayer or multipartformulations cannot be used for a number of applications on account,firstly, of their functionality. Secondly, the production costsresulting from the relatively high level of expenditure of material andmanufacture limit the marketability and acceptance of such products. Forprice-sensitive markets and those where competition is intense, inparticular, it would be desirable to be able to offer inexpensiveproducts of comparatively simple construction for temperature-sensitiveand volatile active substances as well.

The object of the invention is therefore to provide a process forproducing sheetlike active substance formulations comprising asingle-layer matrix, containing active substance, for the controllablerelease of active substances, including volatile andtemperature-sensitive substances, which avoids the disadvantages of theprocesses known from the prior art.

This object is achieved in accordance with the invention by means of aproduction process utilizing process steps described in detail below.

A process is proposed in which the single-layer active substance matrixof the device is produced using at least two layers, identical incomposition, of a base material in the following component steps whichare separated from one another temporally and spatially (ref rencenumerals in accordance with FIG. 1):

a) provision of two prefabricable layers (1, 2), identical incomposition, of a base material,

b) application of active substance to at least one of the two layers (1,2),

c) placement of the two layers (1, 2) atop one another so as to enclosethe active substance applied, and irreversible joining under pressure toform a laminate,

d) storage of the laminate for predeterminable duration under definedconditions, with migration of the active substance into the base layers(1, 2), and connection at their interfaces to form a homogenous matrixfeaturing substantially uniform dispensation of active substance.

Active substances incorporated by this process into the matrix of theformulation include, for example, crop protection agents, biocides,fertilizers, plant strengtheners, cosmetic active principles andfragrances. The matrix layers can comprise one or more activesubstances.

“Biocides”, according to the EC Biocides Directive, which has been inforce since 14 May 1998, are substances or formulations which asintended possess the capacity to kill living organisms or at least torestrict them in their vital function. They are used, inter alia, aswood preservatives, disinfectants, process preservatives, insecticidesand rodenticides. The term “crop protection agents”, which in thepresent specification is used synonymously with “pesticides”, and alsothe term “plant strengtheners”, are defined in §2 of the Crop ProtectionAct applying in Germany.

The term “volatile substances” refers to substances having an effectivevapour pressure even at room temperature. Examples that may be mentionedinclude insecticidal compounds such as dimethoate and acephate or insectpheromones such as Z,E-9,1.2-tetradecadienol andZ,E-9,12-tetradecadien-1-yl acetate.

For the purposes of the present invention, the term“temperature-sensitive” or “thermally labile” substances refers tosubstances which decompose, or whose biological activity is impaired, ata temperature ≧50° C.

In the process of the invention, the single-layer active substancematrix comes about through direct introduction of active substancebetween identical matrix layers, which are subsequently united bypressure and stored for the purpose of “maturation”. The principaladvantage of this process lies in its avoidance of the use of additionalactive substance fixing aids, thereby considerably reducing theexpenditure on material and manufacture and at the same timesignificantly improving the functional quality of the products producedin this way. As a manufacturing process which proceeds at roomtemperature, this process is of particular value for the production ofdevices comprising volatile and thermally labile substances.

Advantageous embodiments of the process according to the main claim canbe inferred by the person skilled in the art from the features of thesubclaims. They relate, for example, to volumetric metering of theactive substance, the operating pressure required when active substanceis admitted into the matrix layer, further process parameters associatedwith the “maturation” of the matrix, the way in which the activesubstance is introduced and applied, the material basis of the matrixbase material, particular properties of the active substance, and itsdesignations.

BRIEF DESCRIPTION OF THE INVENTION

FIG. 1 is a schematic process flowchart; and

FIG. 2 is a sectional view showing the active substance matrix beforeand after storage.

DETAILED DESCRIPTION OF THE INVENTION

In FIG. 1, (1) and (2) denote identical layers of the matrix basematerial, which are present as strip-shaped webs in the form oflaminates on stock rolls (1 a; 2 a). Judiciously, both layers (1, 2) areprovided on both sides with protective layers (3, 4), of which at leastone (3) is detachable. The protective layers (3, 4) can consist ofvarious materials such as paper, plastic and textiles, but to must—bymeans, for example, of treatment with silicone be rendered detachable.This is particularly important if the matrix layers (1, 2) areself-adhesive. Prior to the application of the active substance, bothprefabricated base material layers (1, 2) are exposed by the removableprotective layers (3, 4) being peeled off and taken up by correspondingwinders (5, 6).

Another configuration possibility for the process of the inventionconsists, for example, in the base material layers (1, 2) being providedonly with one web, which is treated so as to repel the matrix on bothsides, and being therefore present in the form of laminate rolls “woundin on themselves”.

In the process of the invention, active substance is metered in the formof a flowable medium. The active substance medium is in a stockcontainer (7) which is connected via a hose (8) to a metering station(10). The active substance medium is therefore located within a closedsystem, which is of decisive importance in the case of volatilesubstances in particular.

Conveyance of the active substance medium into the metering station (10)is the function of a feed unit (9), which in the case of the process ofthe invention can be a hose pump, for example. However, it is alsopossible to use other kinds of pump suitable for metering, such as gear,screw, centrifugal or reciprocating pumps. It is essential for thepurposes of the invention that the feed unit ensures pulseless conveyingwith a meterable conveyed quantity and constant pressure. A uniformconveyed flow is vital for uniform supplying of the metering station(10) with the active substance medium.

In the process of the invention, the metering station (10) consists, forexample, of an active substance dispenser (11) and one or moreapplicator nozzles (12). The active substance dispenser (11) used in theprocess of the invention can comprise, for example, so-called NEMO Robodispensers operating in accordance with the principle of rotatingpositive-displacement pumps. This functional principle of the dispenseris advantageous for the production process in that the conveyed amountof active substance medium is directly dependent on the rotor speed; itcan be altered steplessly and adapted without problems to therequirements of the process. Different-sized constructions can beassigned different “metered-amount ranges”; as a result of the rotarymode of operation, the pressure exerted on the active substance mediumremains constant.

Observing the uniform pressure, which is ≦12 bar, is of essentialimportance to the invention in terms of metering accuracy.

A further advantage of this dispenser (11) lies in the possibility ofreversing the conveying direction, which results in a short break in thethread. This prevents the accumulation of medium at the endpoints of theapplication and ensures uniform distribution of the active substancemedium on the weblike matrix (14).

This is of particular importance for formulations in accordance with theprocess of the invention. Nonuniform distribution of the activesubstance between the base material layers (1, 2) would result in anonhomogenous distribution of active substance in the matrix of thefinished product and would, ultimately, have an adverse effect on thedesired active substance release profile.

In this process, uniform distribution of the active substanceformulation is the function of the applicator nozzles (12). Their numberand arrangement are chosen so that the available matrix area is providedevenly with active substance medium. Judiciously, the application can bearranged in patterns such as stripes, dots, circles or other geometricshapes. These patterns can be produced in either intermittent or rotaryoperating mode, preference being given to the latter mode since itgenerally permits higher production rates.

In the production process of the invention, active substances aremetered in the form of a flowable medium whose viscosity can vary withinwide limits but is at least 1000 mPa.s. Indeed, in the case of liquidsof low viscosity, there can be unwanted flow of the medium on thematrix. This adverse effect would be intensified further in the courseof the subsequent lamination under pressure. For establishing thedesired minimum viscosity, viscosity-increasing additives such as, forexample, AEROSIL® or polymers are useful, which can be either of naturalorigin, such as gelatine or derivatives of starch, for example, or ofsynthetic origin, such as polyacrylic acid, for example.

In order to establish the desired viscosity range it is judicious tothermally condition the application equipment.

In accordance with the invention, the laminating operation, which takesplace directly after the metering of the active substance, can beperformed at a pressure of between 2 and 10 bar. A particularlyadvantageous pressure range is that from 3 to 5 bar. In lamination, bothbase material layers (1, 2) are joined and irreversibly bonded under theeffect of pressure. It is necessary to choose the laminating pressuresuch that the active substance medium does not emerge at the edges ofthe weblike matrix (14) and such that the interfaces of the basematerial layers (1, 2) are bonded inseparably.

A particularly advantageous possibility for configuring the productionprocess of the invention consists in that base material layers (1, 2)and the matrix (14) formed from them have been made self-adhesive. Thissignificantly facilitates the formation of the single-layer matrix (14)and additionally increases the shear stability of the finished product.

When the production process is carried out, the active substance mediumcan also have adhesive properties. A person skilled in the art canreadily achieve this by means of tackifying additives, such as resins,for example.

The matrix-forming layers (1, 2) which are used in the process canconsist of different materials. It is essential to the invention,however, that they are identical in terms of their composition andinclude a polymer or polymer mixture.

Suitable polymers in principle are all those which are able to take upand releas active substances and which can be processed to films. Thefollowing groups may be mentioned as particularly suitable matrixpolymers: ethylene-vinyl acetate copolymers, block copolymers, e.g.styrene/butadiene/styrene or styrene/isoprene/styrene, polyisobutylene,polyacrylates, polymethacrylates, polyvinyl esters, polyamide,polyesters, cellulose derivatives and silicones.

The selection of the polymer for base material layers (1, 2) is guidedby the chemical and physical properties of the active substance.

Depending on the use of the formulation according to the invention,active substances from different groups can be used, such as cropprotection agents, biocides, fertilizers, plant strengtheners, cosmeticactive principles and fragrances, for example. The active substances,which following metering and lamination are firmly enclosed in themiddle of the matrix (14), diffuse, in accordance with FIG. 2 and inagreement with Fick's laws of diffusion, until they have attained asubstantially uniform distribution within the matrix (14). This process,which is referred to as “maturation”, is specific to the activesubstance and dependent on both time and temperature, and can bedetermined by the person skilled in the art. Advantageous embodimentscomprise one or more of the active substances dimethoate, imidacloprid,fenpropidine, acephate and acetamiprid.

The duration of this phase of the production process of the inventioncan be shortened to a desired time by way of the nature of the operatingparameters during storage of the laminate. It is important, however,that the storage temperature does not exceed the critical range for theactive substance in question. The range 15-30° C. and, in particular,20-24° C. may be mentioned as a favourable storage temperature.

In a modification of the process of the invention, the maturationstorage of the active substance matrix (14) can be followed by coolingat a temperature between 3 and 10° C. This has a positive effect on thecohesion and thus on the shear stability of the matrix (14) and isfavourable to its mechanical strength in the case of punching orcutting.

In further process steps, the single-layer matrix produced in accordancewith the invention, as shown in FIG. 2, is combined with otherfunctional layers and then processed to give individual plaster-likeformulations.

The invention is described below with reference to an example, whichrepresents a preferred embodiment of the invention.

EXAMPLE

In FIG. 1, the web (1 a) is a laminate whose width, for example, is 54mm and which, as viewed from bottom to top, consists of a 36 μm thickPET support film, a 125 g/m² base material layer made of polyacrylate,and a siliconized protective layer (95 g/m² paper). The second web oflaminate (2 a) is also 54 mm wide and comprises, as viewed from bottomto top, 95 g/m² siliconized paper, a 125 g/m² base material layer,identical with that of the laminate (1 a), and an 80 μm thicksiliconized PE protective film. Before metering, the protective layers(3, 4) of the two laminates (1 a, 2 a) are peeled off and taken up bythe winders (5) and (6). The remaining laminates are taken into thelaminating unit (13) such that the weblike base mat rial layer of thelaminate (1 a) is congruent with the web lying on the counter-roller.

The active substance formulation, which has a viscosity of 1100 mpa.sand comprises 52.46% by weight dimethoate, 34.76% by weightN-methylpyrrolidone and 12.78% by weight colloidal silica, is meteredcontinuously onto the centre of the base material strip (polyacrylatefilm) of the laminate (1 a) by means of three applicator nozzles (12),metering taking place at a pump speed of 850 rpm and a machine runningspeed of 20 m/min. The amounts of active substance applied are 0.386 gper 0.64 m of the laminate (1 a). Directly after the active substancemedium has been metered, it is covered with the second base materiallayer (2 a). This operation, referred to as laminating, is carried outunder a pressure of 3 bar.

The resultant matrix laminate (14) containing dimethoate is stored at20° C. for 14 days for the purpose of maturation and subsequently at 6°C. for 24 hours.

The finishing of the formulation, by uniting the matrix (14) with afinal cover, and the subsequent processing, take place in a punching andprocessing unit.

What is claimed is:
 1. Process for producing an article in a form of asheet comprising a single-layer homogeneous matrix containing at leastone active substance for an application site, said at least one activesubstance being selected from crop protection agents, biocides,fertilizers, plant strengtheners, cosmetic active principles andfragrances, said process comprising the following temporally andspatially separate steps: a) applying the at least one active substanceas a flowable medium having a viscosity of at least 1000 mPa·s to atleast one of the two layers, identical in composition of a basematerial, at a pressure ≦12 bar with metering b) placing the two basematerial layers atop one another so as to enclose the at least oneactive substance applied, and irreversible joining of the layers withthe at least one active substance therebetween under pressure of 2 to 10bars to form a laminate; and c) storing the laminate for predeterminableduration under defined conditions to effect migration of the at leastone active substance into the base material layers and connection of thebase material layers at their interfaces to form a single-layerhomogeneous matrix in which the at least one active substance issubstantially uniformly distributed.
 2. Process according to claim 1,wherein the pressure in step b) is 3 to 5 bars.
 3. Method for producinga monolithic single layer laminated sheet matrix containing a releasableingredient, said method comprising performing the steps of: a) providingfirst and second matrix base layers, each of said first and secondmatrix base layers comprising a sheet, having opposite first and secondsurfaces, of an absorbent and permeable polymeric material capable ofabsorbing a flowable substance through said first surface, diffusingsaid flowable substance throughout said polymeric material of saidsheet, and uniformly and continuously diffusively releasing saidflowable substance through said second surface for a predeterminedperiod of time; b) providing a flowable substance having a viscosity ofat least 1,000 mPa·s; and further performing, in the indicated order,the steps of: c) storing said flowable substance in an enclosed vessel,in fluid communication with a plurality of distribution outlets, fromwhich said flowable substance is controllably distributable; d)applying, through said distribution outlets, at a pressure not greaterthan 12 bars, to said first surface of said sheet of at least one ofsaid first and second matrix base layers at a plurality of locationsdistributed over said first surface of said sheet, a predeterminedamount of said flowable substance, sufficient to diffuse into saidpolymeric material of said sheets of said first and second matrix baselayers, and to release a predetermined amount of said flowable substancethrough at least one of said second sheet surfaces, continuously for apredetermined period of time; e) contacting said first surface of saidsheet of said first matrix base layer with said first surface of saidsheet of said second matrix base layer; f) applying sufficient pressureto said contacted first and second matrix base layers to irreversiblyfuse said first and second matrix base layers to one another with saidflowable substance therebetween, forming a monolithic single layerlaminate; and g) permitting said flowable material to diffuse throughsaid permeable polymeric material of said sheet of each of said firstand second matrix base layers, to effect a distribution of said flowablesubstance throughout said first and second matrix base layers under adiffusion driving force until a state of dynamic equilibrium isattained.
 4. Method according to claim 3, wherein said pressure in step(c) is 2 to 10 bars.
 5. Method according to claim 4, wherein saidpressure in step (c) is 3 to 5 bars.
 6. Method according to claim 3,wherein step (f) is performed for a time of at least 48 hours, and at atemperature not exceeding a degradation temperature of said flowablesubstance.
 7. Method according to claim 6, wherein said temperature is15-30° C.
 8. Method according to claim 7, wherein said temperature is20-24° C.
 9. Method according to claim 3, wherein said flowablesubstance comprises an active ingredient.
 10. Method according to claim9, wherein said active ingredient is selected from the group consistingof: crop protection agents, biocides, fertilizers, plant strengtheningagents, cosmetically active agents, fragrances, and pharmaceuticallyactive agents.
 11. Method according to claim 9, wherein said activeingredient comprises one selected from the group consisting of:dimethoate, imidacloprid, fenpropidene, acephate, and acetamiprid. 12.Method according to claim 9, wherein said active ingredient comprisesone selected from the group consisting of: Z,E-9,12-tetradecadienol,Z,E-9,12-tetradecadien-1-yl acetate, and mixtures thereof.
 13. Methodaccording to claim 9, wherein said active ingredient is selected fromthe group consisting of: a volatile substance having a measurable vaporpressure at ambient temperature; and a thermally labile substance havinga degradation temperature or a temperature at which activity thereofdecreases above 50° C.
 14. Method according to claim 9, wherein saidflowable substance further comprises a tackifier.
 15. Method accordingto claim 9, wherein said active ingredient is self-adhesive.
 16. Methodaccording to claim 3, wherein in step (c), said flowable substance isapplied to said first surface of said sheet of at least one of saidfirst and second matrix base layers at a plurality of locationsdistributed over said first surface of said sheet in a predeterminedpattern.
 17. Method according to claim 16, wherein said patterncomprises one selected from the group consisting of: stripes, dots, andgeometric shapes.
 18. Method according to claim 3, wherein in step (a),said polymeric material of said first and second matrix base layerscomprises at least one compound selected from the group consisting of:ethylene-vinyl acetate copolymers; styrene/butadiene/styrene (SBS) blockcopolymers; styrene/isoprene/styrene (SIS) block copolymers;polyisobutylenes; polyacrylates; polymethacrylates; polyvinyl esters;polyamide; polyesters; cellulosic compounds; and silicones.
 19. Methodaccording to claim 3, wherein said sheet of each said first and secondmatrix base layers has a weight per unit area of 125 g/m².
 20. Methodaccording to claim 3, wherein at least one of said sheet of said firstmatrix base layer and said sheet of said second matrix base layer has aprotective layer on at least one of its said first and second surfaces,such that when there is a protective layer on only one said surface,said protective layer is removable; and when there is a protective layeron each said surface, at least one of said protective layers isremovable.
 21. Method according to claim 20, wherein said protectivelayers are peelable.
 22. Method according to claim 20, wherein saidprotective layers are selected from the group consisting of papers,plastics, and textiles.
 23. Method according to claim 22, wherein saidprotective layers are coated with silicone.
 24. Method according toclaim 20, wherein said protective layer is removed from at least onesheet surface of one of said first and second matrix base layers beforestep (d).
 25. Method according to claim 20, wherein both said sheet ofsaid first matrix base layer and said sheet of said second matrix baselayer have a protective layer on at least one of their respective firstand second surfaces.
 26. Method according to claim 25, wherein both saidsheet of said first matrix base layer and said sheet of said secondmatrix base layer have a protective layer on both of their respectivefirst and second surfaces.
 27. Method according to claim 3, wherein saidsheet of said first matrix base layer and said sheet of said secondmatrix base layer are continuous strips.
 28. Method according to claim27, wherein said strips are in rolls.
 29. Method according to claim 20,wherein at least one of said first and second surfaces of at least oneof said sheet of said first matrix base layer and said sheet of saidsecond matrix base layer has a support layer thereon.
 30. Methodaccording to claim 20, wherein said protective layers have a thicknessof 80 μm.
 31. Method according to claim 29, wherein said support layerhas a thickness of 36 μm.
 32. Method according to claim 23, wherein saidprotective layer is a siliconized paper.
 33. Method according to claim32, wherein said siliconized paper has a weight per unit area of 95g/m².
 34. Method according to claim 27, wherein said strips have a widthof 54 mm.
 35. Method according to claim 9, wherein said flowablesubstance further comprises an additive.
 36. Method according to claim35, wherein said additive is colloidal silica.
 37. Method according toclaim 35, wherein said additive is a iscosity increasing agent. 38.Method according to claim 36, wherein said flowable substance comprises52.46 wt % dimethoate, 34.76 wt. % N-methylpyrrolidone, and 12.78 wt %colloidal silica.
 39. Method according to claim 3, wherein there arethree distribution outlets.